The present invention relates generally to paper slitting machines, and, more specifically, to alignment thereof.
The ubiquitous paper roll is found in various sizes for various applications including cash registers, ATM machines, adding machines, and receipt printers. Each roll typically includes a paper or plastic core around which is wound a continuous ribbon of paper.
Paper rolls are typically produced in a slitting machine in which a large mill roll of paper is mounted at one end of the machine, unwound through the machine, and then slit at numerous locations along its width to provide corresponding ribbons which are then wound on corresponding cores commonly mounted on a supporting arbor or mandrel. The slitting operation is effected by a pair of circular knives or blades which slit the web in a typical shear cut for each of the cores.
In a single production run of paper cores, several cores are mounted coaxially around the supporting arbor in longitudinal abutting contact therebetween, and fixedly mounted on the arbor by end fittings or nuts. The arbor is then mounted in the slitting machine.
The slitting blades in the machine are typically arranged in pairs on opposite sides of the paper web with the corresponding cutting or shearing lines thereof being suitably aligned with the respective joints between the cores on the arbor.
In one conventional slitting machine, a row of first circular slitting blades are mounted on a first shaft on one side of the web and driven during operation through an end yoke thereof. The first blades are separated from each other by corresponding precision spacers, and thin shims as required to precisely align the cutting edges of the first blades with the corresponding joints between the cores.
A set of second circular blades are pivotally mounted on a second shaft in the machine to selectively engage or disengage the corresponding first blades. Each of the second blades is conventionally mounted in a supporting holder which may be adjusted in position along a supporting dovetail attached to the second shaft. The individual holders may then be adjusted along the dovetail for properly engaging the second blades with their first blade counterparts to control the precise width of each ribbon slit from the web, and also control the cutting overlap or depth between the pairs of first and second blades.
Since each production run of paper cores requires the set up of the individual cores on the arbor, alignment thereof with the first blades, and corresponding alignment of the second blades with the first blades requires considerable time during the set up and alignment procedure. Since the first and second blade sets are integral parts of the slitting machine itself, and the arbor must be suitably mounted therein, the slitting machine cannot be operated during the set up procedure which correspondingly reduces the throughput of the machine, and therefore affects cost of operation.
Accordingly, it is desired to provide an improved slitting machine in which downtime for set up of each production run may be minimized for maximizing use of the machine.